Coated sheet material



June 2o,l 1939. F WILLMMS 2,162,769

COATED SHEET MATERIAL Filed NOV. 20, 1957 Patented June, 240, 1.939'

UNlTl-:D STATES :PATENT OFFICE i COATED SHEET MATERIAL Floyd E. Williams, Gary, rnd., assignor to inarbon Corporation.. Gary.' Ind., a, corporation of Delaware Application November 2o, 1937, serial No. 175,544

4 Claims.

10 containing a softener which may be heat sealed in a secure manner.

Another object is to provide a c oated paper containing a softener which may be heat sealed Without causing migration of the softener from the paper into the sealing medium. i

A further object is to provide a heat sealed paper bag of neat andeattractive appearance.

Other objects and advantages will become apparent as the following detailed description pro- 20 gresses, reference being had to the accompanying drawing wherein:

Fig. 1 represents a cross-section ofA a coated sheet showing the relative positions of the different coatings.

25 Fig. 2 represents a perspective View of a bag made from the sheet illustrated in Fig. 1 and illustrating the sealing feature.

Fig. 3 is-a diagrammatic View showing an arrangement for sealing together the coated sheet l, material.

. In accordance with my invention, sheet material is coated with alm-forming composition of a predetermined softening point to forma coated sheet. On one side of this coated sheet IV 35 then' apply a coatingv of a film-forming composition which has a lower softening point than that of the" underlying composition.-

Referring to the drawing in which a preferred form of my invention is illustrated, there is shown w a sheety I of paper having a coating 2 on bothl sides. On one side of the coating 2 Ais a coating 3 of a film-,forming composition which has a lower softening point than that of the-composition of coating 2. L51' One embodiment of my invention is a bag (shown in Fig. 2 as a flat type of bag, but it is to be understood that a bellowsftype is' included) formed from my coated sheet material, vthe coating 3 of the low softening point composition' o being on the inside of the bag.

The sides and bottom of the bag are sealed together along the marglnal edges 4 and 5, as shown in Fig. 2, by applying heat4 and pressure by means of a roller 6, shown in Fig. 3, or some 5 other heat sealing mechanism.

n win Vbe noted from Fig. 3 niet the heat sealing mechanism 6 is 'applied to the outside high-softening point composition 2. The heat vand pressure' are so regulated that theywill be insuflicient to melt and materially deform the high-softening point composition 2, but will be sucient to soften and render adherent the low- .softening composition 3.

The base sheetmaterial I is preferably. paper containing a softener. Various types of paper 10 may be used, such as any of the papers commonly used inmaking bags, including kraft, sulphite paper, glassine, and parchment. The softeners which may be suitably used in the paper include glycerine, ethylene glycol and other softeners 16 rwhich have been used to render paper more pliable and decrease its permeability. i A suitable paper may contain y% of glycerine.

The coating 2 which is applied directly to .the paper may suitably be any composition which is 20 flexible in thin lm form and which has a higher softening 'point than coating 3. Preferably, it

should be relatively hard and non-tacky at room temperature. 'Coating3 may be of any flexible composition which has a lower softening pointA vthan coating .2 and which becomes tacky and adhrent on the application of heat.

` Many film-forming materials will become apparent for use from the above. Some suitable combinations are given in the following table:

High softening Low softening Chlorostannic acid or phenol typevrubber Cellulose acetate. l

condensation defivatives. Do Rubber hydrochloride. Rubber hydrochlo- Rubber'hydrochlonde (amorphous type).

ride (crystalline v I Rubber hydrochlo Chlorostannic acid or phenol-` type rubber ride. condensation derivatives. Cellulose acetate. Ethyl cellulose. Rubber hydrochlo- Chlorostannic acidA or phenol type l'llbber 40 ride. isomerparaiin wax.

The above materials are examples of base'llmforming ingredients. Other ingredients may be incorporated therein for various purposes, asfor 4'5 modifying the softening point (for example, lowsoftening resins) increasing water resistance (for example, waxes), -or for plasticizing (plasticizers for each of the above materials are well-known) The rubber hydrochloride designated as crystalline type hydrochloridels the general type of rubber hydrochloride described in patents to Bradley and McGarvack, No. 1,519,659, and to f' Calvert, No. 1,989,632, and may be made by reacting solutions of rubber with hydrogen chloride. A similar slightly higher softening material may be made by reacting solid sheet rubber with gaseous hydrogen chloride at elevated temperatures. The softening point of crystalline rubber hydrochlorides may be lessened by making a partially saturated rubber hydrochloride rather than saturated rubber hydrochloride. The amorphous rubber hydrochloride is described and claimed in Gebauer-Fuelncgg and Moifett application, Serial No. 30,515. This material may be obtained by reacting thin sheet rubber withliquid hydrogen chloride at `85 C.

The chlor-stannic acid rubber condensation derivatives mentioned in the table may be obtained by reacting solutions of rubber with chlorostannic acid, pouring the product into water and isolating the condensation derivative from the liquid by steam distillation. They are. described in various patents and other publications, including patents to Bruson, No. 1,797,188, Gehman, No. 2,050,209, and to Endres No. 2,052,391.

.The phenol type rubber isomer is a resin-like, `low-flowing condensation derivative of rubber and may be made by reacting rubber with phenol I and hydrogen chloride.

'Ihe coating compositions may be applied by means well-known to the art. The sheet to be coated may be sprayed, brushed or dipped with solutions of the ingredients in a volatile solvent and the solvent evaporated, leaving the coating or layer of vsolid. material. Moreover, pre-formed films may be laminated to the paper by means of heat and pressure.

The low-softening coating is preferably applied so as to entirely cover the paper and the inside of l the bag made therefrom. However, the low-soften ing material may be applied in-strips along the marginal edges so that it will serve as a thermoplastic sealing medium in forming a bag. Thus, for example, a narrow strip of low-softening adhesive may be applied over the higher softening layer solely along edges 4 and 5.

VVarious other modifications of the invention `may be made, 'and it is to be understood that the invention is not to be considered as limited by the specific examples herein given as illustration of the invention, except as may be necessitated by the prior art.

Having thus described my invention, What I claim as new follows: V

l. Water and oil resistant sheet material suitable for the manufacture of heat sealed containers comprising a fibrous cellulosic base having a water soluble softener incorporated therein, a layer of crystalline rubber hydrochloride attached to each side of said base, and a layer of amorphous rubber hydrochloride attached to a layer of crystalline rubber hydrochloride solely on one side of s aid base.

2. Water and oil resistant sheet material suitable for the manufacture of` heat sealed containers comprising a base of paper in sheet form containing a water ,soluble softener, a thin coating of crystalline rubber hydrochloride forming a thin continuous coat on each side of said base, and on said coating of crystalline rubber hydrochloride on solely one side of said base, 'a thin coating of amorphousrubber hydrochloride.

3. Water and oil resistant sheetmaterial suitable for the manufacture of heat sealed containers comprising a thin sheet of fibrous cellulosic material softened with a water soluble polyhydroxy alcoliciI a thin thermoplastic surface'coating of rubber hydrochloride on one side of said cellulosic sheet, and dispersed between said sheet and said surface coatingand retarding migration of said polyhydroxy alcohol from said sheet a thin continuous coatinglof a rubber hydrochloride of higher now point than 'said rubber hydrochloride of the surface coating.- l

4. Water and oilresistant sheet material suitable for the manufacture of heat sealed containe'rs comprising a thin sheet of paper softened with a water soluble polyhydroxy alcohol, a thin ther,

moplastic surfacecoating of amorphous rubber hydrochloride on one side of said celluluosic sheet, and dispersed between said sheet and said surface coating and retarding migration of said polyhydroxy alcohol from said sheet a thin continuous coating of substantially saturated crystalline rubber hydrochloride. v FLOYD E. WILLIAMS. 

